Polyoma virus middle T antigen

Protein phosphorylation is one of the most important mechanisms in the regulation of cellular function. Proteins can be phosphorylated on serine, threonine or tyrosine residues. Most phosphorylation occurs on serine and threonine, with less than 1% on tyrosine (see Ch. 23). This perhaps accounts for the late discovery of tyrosine phosphorylation, which was found first on polyoma virus middle T antigen in 1979 by Hunter and colleagues [1,2]. 

Segawa, K., and Yamaguchi, N., 1986, Characterization of the chimeric SV40 large T antigen which has a membrane attachment sequence of polyoma virus middle T antigen. Virology 155 334-344. 

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